Leather laminate for camera housing

ABSTRACT

A leather-enhanced product is prepared by treating the flesh side of a leather element with an adhesive material, adhering to the treated side of the leather element a component with greater inherent rigidity than the leather, which component serves to bridge the leather element and a pressure-sensitive adhesive layer, applying a pressure-sensitive adhesive to the side of the stiff component opposed to the leather element and adhering therewith the composite leather laminate to a stratum.

I United States Patent 1191 1111 3,886,986

Renzullo et a1. 1 1 June 3, 1975 [541 LEATHER LAMINATE FOR CAMERA 3,021.250 2/1962 LaVoie 161/406 HOUSING 3,423,276 1/1969 Eckenroth 161/167 [75] Inventors: Andrew Renzullo, Nashua, N.H.; OTHER PUBLICATIONS George D. Suokko, Plainville, Mass. Waterer, Leather in Life, Art & Industry, pp. 215. 216, plates LXXlV, LXXV and XCI, pub. 1943. [73] Asslgnee' 3:25 Carporatlon Cambndge' Leland, Leather Work, pp. 34-37 inclusive. pub. by

' Whittaker & Co., London, 1892. [22] Filed: Oct. 24, 1972 Primary Examiner-George F. Lesmes [2]] Appl' 300l57 Assistant Examiner-R. J. Roche Attorney, Agent, or Firm-Sheldon W. Rothstei'n; [52] U.S. Cl. 150/52 J; 161/226; 161/D1G. 2; Susan M. Cooke 161/213; 161/167; 354/288 [51] Int. Cl B65d 65/14; B65d 65/40 [57] ABSTRACT [58] Field of Search 61/1671 2; A leather-enhanced product is prepared by treating 36/68 72? 354/288 150/52 J the flesh side of a leather element with an adhesive material, adhering to the treated side of the leather el- [56] Rderences C' ement a component with greater inherent rigidity than UNITED STATES ENTS the leather. which component serves to bridge the 2,020,007 11/1935 Wagman 161/226 leath r elem nt and a p ssur -s ti iv 2.323.342 7/1943 McManus et a1.... layer, applying a pressure-sensitive adhesive to the 2.522.68 9/1950 Le0 dside of the stiff component opposed to the leather ele 7 4/1956 ment and adhering therewith the composite leather 2,858,248 10/1958 Hastings........... laminate to a stratuln 2,946,713 7/1960 Dusina ct a1 161/226 2,961,365 11/1960 Sroog 161/226 9 Claims, 2 Drawing Figures LEATHER LAMINATE FOR CAMERA HOUSING BACKGROUND OF THE INVENTION For many applications, it is desirable to employ treated animal skin, hereinafter generally referred to as leather, as a component of a manufactured product. While numerous synthetic materials may be utilized to provide similar utilitarian functionality in terms of aesthetics and pleasing aroma leather is unsurpassed. However, the drawbacks in employing natural leather often contraindicate its use. Among such drawbacks is the fact that leather changes size rather drastically under different temperature and humidity conditions. Consider the effect on a leather insert which is fastened to a camera body, for example, by means of a pressuresensitive adhesive. With changes in humidity, the leather insert may shrink a substantial amount. As it shrinks, it causes its original peripheral areas to pull away from the camera body, thereby leaving exposed the tacky surface of underlying adhesive. Lint, for example, from a pocket or drawer, or dust which may be present under ambient conditions, will quickly embed itself into the tacky adhesive and render the area aesthetically disappointing to a viewer. On a product as described, the employment of contact and similar nonpressure-sensitive adhesives on a stratum surface is undesirable since they generally do not permit removal of the leather without leaving messy residues which must be removed before another element may be adhered to the stratum. In addition, the use of thermosensitive adhesives against a polymeric stratum is generally inappropriate since, under the thermal conditions employed, the base stratum is subject to degradation and deformation.

By means of the present invention, a laminate comprising leather is prepared and overcomes the drawbacks of employing leather to provide an aesthetically pleasing product. Specifically, by means of the present invention, the heretofore tolerated shrinkage conditions which permit an unsightly tacky border around the edges of a leather insert are obviated, while at the same time the leather insert achieves a degree of stiffness which renders it capable of automatic application to a selected stratum by means of conventional massproduction equipment.

OBJECTS OF THE INVENTION It is the principal object of this invention to provide a leather-containing laminate which is adapted to be adhered to a selected stratum to provide aesthetic as well as utilitarian functionality to such stratum and will not cause its area of contact with the stratum to diminish under a variety of temperature and humidity conditions.

It is another object of the present invention to provide a laminate comprising leather which additionally contains a stiff component which serves to bridge the leather with a pressure-sensitive adhesive material.

It is still another object of the present invention to provide a method whereby a leather-containing laminate is prepared by treating the flesh side of a leather element with a preferably thermo-sensitive adhesive, adhering a stiff component to the leather element and treating the side of the stiff component opposed to the leather element with a pressure-sensitive adhesive ma terial.

It is still another object of the present invention to increase the stiffness of a leather element and thereby render such element capable of automatic handling in a mass-production leather laminate application system.

It is still another object of the present invention to provide a photographic camera which comprises a leather element capable of enhancing the visual impact of the camera aesthetically and, at the same time, providing a pleasing covering for screw-retaining holes and other mechanical assembly ports of the camera.

One other object of the present invention is to provide a laminate of the aforementioned type and a method for applying such a laminate to a stratum whereby the laminate may be adhered to the stratum without heating either the stratum or the leather component of the laminate to an extent wherein deleterious results ensue and whereupon the laminate may be re moved from the stratum without causing a messy adhesive residue to remain on the stratum.

Further objects and advantages of this invention will in part be obvious and will in part become apparent as the following description proceeds. The features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the present invention, reference may be made to the following detailed description taken in connection with the accompanying drawings wherein:

FIG. 1 is an exploded perspective view showing the components of the leather-containing laminate and a suitable stratum adapted to receive the laminate in assembly relationship; and

FIG. 2 is a schematic flow diagram of the method of the present invention depicting a preferred technique for preparing the leather-containing laminate of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates the preferred embodiment of the present invention in an exploded perspective view. As denoted, a typical stratum l is shown with various holes and access orifices through which fastening means and other assembly devices may be employed to secure the stratum to an appropriate superstructure or chassis. Element 2 is leather which has adhered to its flesh face (most proximal to stratum 1) layer 3, which comprises a preferably thermo-sensitive adhesive which preferably provides sealing functionality. In direct contact with layer 3 is stiff component 4 which, among other things, serves the function of bridging adhesive layer 3 with pressure-sensitive adhesive layer 5. In this preferred embodiment, rather than employing a single coating of pressure-sensitive adhesives on the side of stiff component 4 most proximal to stratum l, a system comprising a double-sided pressure-sensitive adhesive tape 6 including carrier is employed. The tape, in addition to pressure-sensitive adhesive layer 5, comprises pressure-sensitive adhesive layer 7. At such time as the operator is prepared to adhere the composite structure comprising the leather element to stratum 1, release paper 8 is peeled from the surface of adhesive layer 7 and the exposed adhesive side of the leather-containing laminate is contacted with the surface of stratum l.

Referring now to the schematic flow diagram of FIG. 2, the preferred method for preparing the leathercontaining laminate of the present invention will be described in detail. A treated animal skin 10, as it comes from the tanner, is passed through a click die station where it is cut into a rough blank out of which the ultimate desired configuration will be cut at a subsequent station. The die-cutting operation is conventional and well known in leather-forming arts. In its present condition, the leather still contains on its flesh side unwanted material and is of uneven thickness as shown in side view 17. In order to provide a uniform thickness to the die-cut pieces, they are next fed through a slitter whereupon a portion of the flesh side of the leather is removed resulting in side view 18. At this point the leather is preferably between twelve and thirty mils thick. Following slitting, the cut leather pieces are fed onto a conveyor, flesh-side up, and are sprayed, preferably with a solvent-dissolved hot melt thermo-sensitive adhesive 12 through nozzle 13 at about room temperature. Since the first coat of adhesive material is quite readily absorbed by the leather, it has been found that a second coat provides enhanced results by reaching the entire nap of the flesh side of the leather, reducing it to a substantially flat configuration and providing a sealing function.

A stiff material 14, which is preferably a thin web of metal of approximately the same width as the cut leather, is heated and led past a gravure roll, doctor blade or other suitable coating system for applying a layer of preferably thermo-sensitive adhesive. After the adhesive is applied, the coated material is kept hot by preferably employing a bank of infrared lamps 15 and is suitably pressed onto the coated stiff material at station 19. Onto the hot adhesive is then placed the treated leather pieces, flesh sides down. The hot adhesive-coated web bonds firmly with the adhesive-treated leather to provide a strong bond. After the composite leather-web structure cools, the side of the web opposed to the leather is treated with a pressure-sensitive adhesive, preferably by having adhered thereto a double-sided pressure-sensitive adhesive tape 16 with a release layer adhered to the side thereof opposed to the stiff web. After the adhesive tape 16 is adhered to the composite structure, the web enters a stamping station where the individual leather pieces are accurately cut out of the stiff web to be stored for subsequent assembly onto an appropriate stratum. According to the desires of the operator the stamping operation may be carried out in one or more steps. ideally, the stamping step will not only perform the function of cutting from the stiff material web the finished leather-containing laminate, but will provide the additional function of providing to the leather portion a slight radius or bevel. it has been found that greater accuracy is achieved by utilizing two dies one to form an appropriate radius or bevel on the leather and the second to complete the cutting operation by cutting through the stiff material and pressure-sensitive tape components. Subsequent to the stamping operation the leather laminates may be stacked and sprayed along their edges with an appropriately colored paint.

Among the many types of materials which can be used to adhere the leather element to the stiff component are rosin-based adhesives; shellac; asphaltics; inorganic adhesives such as sodium silicate; polyvinyl acetate; polyvinyl alcohol; acrylic adhesives; nitrocellulose; oleo resins; polyesters; vinyls; phenolics; resorcinols; epoxies; urea materials; melamines; alkyd adhesives; rubber adhesives including nitriles, butadienestyrene materials, silicones; etc. The principal criterion by which the adhesive system employed to bond the leather element to the stiff component is that it be capable of providing enhanced characteristics over those provided by a pressure-sensitive type system, such as stronger bonds, substantially no creep, etc. Pressuresensitive adhesives have been found unsatisfactory for providing sufficient bonding strengths. For purposes of this treatment, a pressure-sensitive adhesive is one considered to display substantially permanent tackiness and universal adhesion. It is considered to impart to a surface the characteristic of requiring only temporary pressure to achieve adhesive bonding. Nonpressuresensitive adhesives falling within the categories described hereinabove are well known to those having or dinary skill in the art and, while thermo-sensitive adhesives and particularly thermo-sensitive adhesives of the polyester type are preferred for utilization in the pres ent invention, such other appropriate adhesives as may be available and are capable of providing the strength to the leather-stiff component bond required for the present invention may be employed. The particular adhesive preferred for employment in the present invention to treat the leather and subsequently bond it to the stiff component is Terlan 6103, a saturated lower molecular weight Dacron polyester material manufactured by the Terrell Corp. of Wilmington, Mass, U.S.A. it is preferably hot-coated onto the stiff material web in a thickness of from 3 to 5 mils and provides a bond strength greater than about 30 pounds per linear inch. It is preferably sprayed onto the flesh side of the leather in a solution which preferably employs trichloroethylene as the solvent.

The stiff component employed in the present invention is preferably metallic and will preferably impart to the leather to which it is adhered a rigidity sufficient to permit the leather composite laminate to be employed in a mass-production automatic assembly system; that is, to be handled automatically without having an insufficient rigidity to lend itself to automation. In addition, under various conditions of humidity, as has been aforenoted, the leather component tends to shrink and, accordingly, applies stress to the stiff component about its periphery which tends to cause an upward curl on the side of the leather. The rigidity of the stiff component combined with the effect of the pressure-sensitive adhesive against a suitable stratum must be sufficient to overcome the curling tendency. in the present invention, as the leather shrinks, the upper laminae of leather tend to move toward the center of the leather element while the adhered portion stays fastly in place, thereby causing what might be considered a slightly greater radius than was initially cut into the leather while still maintaining its aesthetically pleasing characteristics. The preferred stiff component is an aluminum web preferably about five mils thick and ASM designated 3003-11 18 series, or equivalent.

While the stiff material may be coated on its side opposed to the leather element with a pressure-sensitive adhesive, using conventional application apparatus, it is preferred to employ a double pressure-sensitiveadhesive-coated tape having a release sheet on one side. The bond between the tape and the stratum should be at least five pounds per linear inch. The preferred pressure-sensitive materials for employment in this invention are synthetic rubbers. In the preferred embodiment, a polypropylene tape coated on each side with a synthetic rubber adhesive is employed. The suggested material is Fastape H, a product of the Fasson Corporation of Gainsville, Ohio, U.S.A.

It will be appreciated that by the present invention a system has been devised whereby a product may have access ports, screw-holes, etc. camouflages with an attractive leather insert which does not betray the presence of such discontinuities in the substratum due to the stiff layer which prevents the leather from taking the set of the stratum discontinuities. In addition, at such time as access is desired to the various screws, ports, etc., due to the fact that the leather is adhered to the stratum by pressure-sensitive material, it may be readily peeled of and leaves no unsightly adhesive residue which would present a substantial cleaning problem before the unit can be reassembled. In addition, due to the fact that the present system controls leather shrinkage, pieces made pursuant to the present invention need not be stored under controlled humidity conditions as now is the practice in the leather industry.

Bonding strengths, as referred to above, are measured using a standard T pull system wherein each of the bonded materials is drawn directly from the other and the force required to cause the components to pull apart is measured.

Throughout the specification the term stiff has been used to describe a laminate component. As emplayed, it connotes a degree of rigidity substantially greater than that of the leather element to which it is joined, but is not so rigid as to be unyielding. Furthermore, the term flesh side" has been employed with respect to the leather element and connotes the side thereof that was originally adhered to the flesh of the animal from which it was removed.

The present invention is not limited to the particular details of construction of the embodiments depicted and it is contemplated that various modifications in applications will occur to those skilled in the art. Therefore, because certain changes may be made in the above-described method and product without departing from the true spirit and scope of the invention herein claimed, it is intended that the subject matter of the above shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a photographic camera which includes a camera housing, the improvement wherein said housing has adhered thereto by means of a layer of pressure-sensitive adhesive, in inverse order:

a leather element having a surface adapted to be exposed to the environment;

a layer of adhesive substantially continuously coated over the surface of the leather element opposed to the surface adapted to be exposed to the environment; and

a metallic component stiffer than said leather element adhesively attached to the coated side of the said leather element.

2. The invention of claim 1 wherein said stiff metallic component is comprised of aluminum.

3. The invention of claim 1 wherein the adhesive functional material adhered to said leather element comprises substantially the same material as that employed to adhesively attach said stiff component to said leather element.

4. The invention of claim 3 wherein said adhesive functional material contains a thermosensitive adhesive.

5. The invention of claim 4 wherein said thermosensitive adhesive is a polyester material.

6. The invention of claim 1 wherein said layer of pressure-sensitive adhesive comprises a tape coated on both sides with pressure-sensitive adhesive.

7. The invention of claim 6 wherein the adhesively coated side of said tape furthest from said leather element is covered by a release sheet.

8. The invention of claim 1 wherein said leather element is between 12 and 30 mils in thickness.

9. The invention of claim 8 wherein said metallic stiffening component is about 5 mils in thickness. 

1. IN A PHOTOGRAPHIC CAMERA WHICH INCLUDES A CAMERA HOUSING, THE IMPROVEMENT WHEREIN SAID HOUSING HAS ADHERED THERETO BY MEANS OF A LAYER OF PRESSURE-SENSITIVE ADHESIVE, IN INVERSED ORDER, A LEATHER ELEMENT HAVING A SURFACE ADAPTED TO BE EXPOSED TO THE ENVIRONMENT, A LAYER OF ADHESIVE SUBSTANTIALLY CONTINOUSLY COATED OVER THE SURFACE OF THE LEATHER ELEMENT OPPOSED TO THE SURFACE ADAPTED TO BE EXPOSED TO THE ENVIRONMENT, AND A METALLIC COMPONENT STIFFER THAN SAID LEATER ELEMENT ADHESIVELY ATTCHED TO THE COATED SIDE OF THE SAID LEATHER ELEMENT.
 1. In a photographic camera which includes a camera housing, the improvement wherein said housing has adhered thereto by means of a layer of pressure-sensitive adhesive, in inverse order: a leather element having a surface adapted to be exposed to the environment; a layer of adhesive substantially continuously coated over the surface of the leather element opposed to the surface adapted to be exposed to the environment; and a metallic component stiffer than said leather element adhesively attached to the coated side of the said leather element.
 2. The invention of claim 1 wherein said stiff metallic component is comprised of aluminum.
 3. The invention of claim 1 wherein the adhesive functional material adhered to said leather element comprises substantially the same material as that employed to adhesively attach said stiff component to said leather element.
 4. The invention of claim 3 wherein said adhesive functional material contains a thermosensitive adhesive.
 5. The invention of claim 4 wherein said thermosensitive adhesive is a polyester material.
 6. The invention of claim 1 wherein said layer of pressure-sensitive adhesive comprises a tape coated on both sides with pressure-sensitive adhesive.
 7. The invention of claim 6 wherein the adhesively coated side of said tape furthest from said leather element is covered by a release sheet.
 8. The invention of claim 1 wherein said leather element is between 12 and 30 mils in thickness. 